


How to Breathe

by flecksofpoppy



Series: The Air Outside [1]
Category: Shingeki no Kyojin | Attack on Titan
Genre: Alpha/Beta/Omega Dynamics, Anal Sex, Canon Era, Hurt/Comfort, Knotting, M/M, Non-Traditional Alpha/Beta/Omega Dynamics, Omega Erwin Smith, Omegawin, ackerbond, yeah I tagged it omegawin i do what i want
Language: English
Status: Completed
Published: 2017-05-07
Updated: 2017-05-07
Packaged: 2018-10-28 22:53:17
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 17,470
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10841148
Author URL: https://archiveofourown.org/users/flecksofpoppy/pseuds/flecksofpoppy
Summary: There are many secrets in the Survey Corps, whether it’s the latest expedition objective or which noble has financed it, but one of the best kept is more akin to barracks gossip than political revelations.And that's what exactly Commander Erwin Smithis.





	How to Breathe

**Author's Note:**

> This is my first ABO fic, and I have to say thank you to three writers whose ABO SNK fics I’ve read over and over. Some of the mechanics of this universe are undoubtedly gleaned from my love of them. They are: [find me on the way, find me anyway](https://archiveofourown.org/works/5181542) by seabear (eruri); the series [Heats](https://archiveofourown.org/series/258841) by missazrael (jeanmarco, reibert, various); and [Famine and Feast](https://archiveofourown.org/works/5066203) by TiggerYumYum (jean/various). Please read them post-haste! They are absolute treasures.
> 
> A note on my ABO mechanics: in this universe, heat suppressants are also used to suppress scent if administered in certain doses, explained with some gerryrigging of Hanji's scientific advancements, aka the Einstein of ABO SNK. ;D This is also one of the most self-indulgent things I’ve ever written.
> 
> As always, feedback is treasured, especially since this is my first try at ABO. ^_^;; Here we go…

There are many secrets in the Survey Corps, whether it’s the latest expedition objective or which noble has financed it, but one of the best kept is more akin to barracks gossip than political revelations.

And that is what exactly Commander Erwin Smith _is._

A time-honored tradition among brave, albeit stupid, new cadets is to makes bets on who can figure where Erwin sits on a food chain that’s completely different than military rank, and far older than even the Walls.

Most people assume alpha at first glance. It only makes sense given Erwin’s rank, impressive size, and fighting prowess. Everything about Erwin screams alpha, but nonetheless, it’s never actually been confirmed.

But it’s possible to keep such secrets nowadays, thanks in part to Hanji Zoe, who argues that with the right suppressants at a strong enough dose and solid mental disposition, it’s possible to hide it.

If Hanji claims it to be so—a person with absolutely no personal biases when it comes to science—Erwin believes it. Especially since she’d explained ever so helpfully that while Moblit is an omega through and through, no one would ever suspect it unless they were able to smell the scents he gave off during mating or a particularly severe heat, much to Moblit’s mortification since it was reinforced by “personal experience.”

Hanji’s suppressants are so effective, in fact, that some mates opted to take the older, weaker versions or opt out of suppressants altogether, lamenting the intense closeness heats brought on. This was usually beta couples, though, or alphas and betas, since heats are widely known to be absolute misery for omegas.

Erwin’s status is the best kept secret in the history of the Corps. Most people believe that it’s the best kept secret since the origin of the Walls. He doesn’t have a mate, barely reacts to other people’s scents, and spends more time in his office than home or any other place where sex might occur.

There are jokes that Erwin isn’t anything at all—a new type of biology known not as an alpha, beta, or omega, but simply _insane_ —widely respected, but a little bit off in the head. Erwin allows these assumptions to be made, never denies or feeds any particular rumor; it’s a good way to keep any nosy parties on their toes.

That being said, as a man who keeps secrets, Erwin considers three flaws to be the primary causes of a person’s undoing: absentmindedness, overconfidence, and an inflated sense of self-importance. These are qualities which end in early deaths on the field, or the ruination of reputations within the Walls.

Admittedly, he is definitely the first, though he takes great pains to pay attention to the important things. Important things include: nobles who are inclined or disinclined to fund expeditions, murmurings within the Walls about illicit information, and plots of the other military branches. 

On this roster, though, is a smaller detail, though just as important: taking his weekly heat suppressant.

He blames the lapse in attention on paperwork, though he knows really, there’s no one to blame but himself.

His own undoing starts when Mike enters his office one morning, looking sleepy (though Mike has a tendency to always look sleepy). When Erwin glances up to greet him, he suddenly stops dead in his tracks, staring at Erwin with wide eyes. He even brushes the hair out of his face to get a better look, staring, as he shuts the door behind him.

“Good morning, Mike,” Erwin greets, noting the strange behavior in his peripheral vision, but not wanting to comment on it unless necessary. Mike has his quirks, just like everyone else.

It’s been a rough morning—Erwin is wracked with a terrible headache from not sleeping the night before, poring over updates from Zackley of current events inside the Capital. The reports are formal and sent to everyone, but Erwin follows them carefully, picking apart small points of information that anyone else might overlook, fitting them together as he plans for the next milestone in his never-ending campaign to reach the Jaeger basement.

But right now, he simply wishes Levi would magically appear the way he always does with tea, maybe some willow bark to chew to help with the headache.

“Erwin,” Mike greets in return, but his voice is strained.

It’s then, as Erwin attempts to rub the headache away from his temples, that he realizes Mike’s isn’t staring at his face; he’s staring at Erwin’s neck, right where his scent gland is.

They lock eyes, and Mike just gapes. It’s hard to startle Mike Zacharias, second strongest and most taciturn soldier in the Corps, but he definitely looks surprised right now.

“You’re a…” he blurts, and Erwin raises his eyebrows despite himself.

Mike doesn’t know what Erwin _actually_ is, despite the fact that he knows a great deal from years of fighting side by side. Erwin’s trainee class is mostly dead, so there’s no one to pass on any lingering memory of mishaps in his younger years. Even Levi doesn’t know what Erwin is.

Only Hanji is aware of Erwin’s true nature, since she administers the high dosage of suppressants of her own making—much like most sensitive information, it’s on a need-to-know basis.

“What?” Erwin questions, dread growing in his gut as he watches Mike whirl swiftly to lock the door.

“I’d be a rich man if I collected all those bets,” he quips, his voice strained but obviously trying to lighten the mood, “from the idiots who have tried to figure out what you are.”

Mike is an alpha through and through, a fact that surprises exactly no one.

A sudden cloud of pheromones _pours_ off him, which he has the decency to look embarrassed about as he steps back, but the way he’s staring again at Erwin’s neck finally makes sense.

“I forgot,” Erwin blurts, looking down at his desk drawer compulsively, sliding it open. And there, like some harbinger of a terrible future, is the heat suppressant he’d neglected to take for the week.

“You forgot,” Mike echoes dumbly.

Erwin, being the quick-witted person he is, puts it all together at a horrifying speed that makes him feel as if someone threw him onto the back of a deviant Titan and let it run wild.

The headache is not a headache; it’s the onset of a full blown heat, and as Mike’s expression grows increasingly strained, Erwin realizes he must be putting out an immense amount of omega hormones. And this is just the precursor.

“You need to get out of here,” Mike says suddenly blanching, nose twitching despite his urgent words. “You reek.”

“Um…” Erwin replies dumbly, looking at the papers strewn around his desk. “I…”

“You don’t have a choice.” Mike’s voice is panicked now, which jolts Erwin into reality; the last time Mike sounded frantic this was when Nanaba had somehow fallen out of formation and they’d thought she’d been picked off and eaten. “There aren’t any expeditions coming up. We’ll survive for a week.”

A week.

The dread in Erwin’s gut is fast becoming leaden, rooting him to the spot as if he can’t move, poison running through his veins.

He hasn’t actually had to think about the fact he’s an omega in a very long time, but fuck if it’s not all rushing over him now, years of pent up anxiety slamming into him with each second.

Erwin’s no fool, though, and given that he’s survived this long in the Corps, as what less kind civilians call “Titan chow,” his body forces him into action before his mind can catch up, standing to follow Mike’s directions.

It’s a sobering thing to think that it’s also the same body he soon won’t be able to control.

Mike cracks the door open, eyes darting down the hallway to see if anyone is passing by.

“Moblit,” he says placidly, reaching out one quick arm to retrieve the hapless passerby who happens to be Hanji’s assistant, “come here.”

As Moblit is dragged into the room and the door is soundly shut again, he stares at both men, inhales once, and then looks incredulously at Erwin.

“You’re an omega,” Mike remarks unceremoniously to Moblit, “we need your help. Walk with us and talk. I don’t care what it is, but just keep talking and stick close.”

Mike is truly a man of few words, but people do tend to listen to him when he speaks as Moblit just nods dumbly with wide eyes, obviously aware he’s been caught up in a moment of severe duress.

They open the door, Erwin walking slightly behind Mike and Moblit as he starts rambling mundane facts about Titan biology that any trainee could find in a lesson plan. Erwin muses there’s a reason Hanji relies on him so heavily, considering he’s keeping his cool despite finding out that the Commander of the Survey Corps is an omega.

“Whoa,” comes a startled voice. Erwin turns to take in a cadet that’s walking past, and his eyes are wide as he sniffs at the air curiously, stopping in the middle of the hallway until his eyes settle on their group.

Jean Kirschstein is an astute soldier, and presented as an alpha early—Erwin would’ve put his money on beta if he was being stereotypical, given Jean’s aggression is often mixed with brashness—but regardless of what he is, he’s smart and observant at the most inopportune times.

Erwin really doesn’t need a curious alpha cadet snooping around with his nose right now.

Mike’s ploy apparently works, though, as Jean’s eyes finally settle on Moblit. It’s no secret that Moblit is an omega, though no one bothers him about it. In fact, if there’s one thing that’s not tolerated in the Corps, it’s harassment of omegas. Some even opt to join the riskiest faction, simply because the Garrison and Military Police are prone to overlook infractions committed toward omega soldiers. Erwin thinks it’s their way to root out weaklings based upon an asinine assumptions that he does nothing to dissuade, since he ends up with people like Moblit in his command—an omega, extremely intelligent, and able to be around Hanji for more than a few hours at a time.

But there’s no helping biology, and although Jean isn’t the type of cadet to bully or push himself onto an unwilling beta or omega, the inclination to pursue a scent that his instincts are screaming at him to follow means he won’t stop investigating. He’s still standing in the hallway as their group walks away, staring at them.

“Move along, Kirschstein,” Erwin finally says, risking drawing attention to himself. He knows he’s not in a full heat, but he’s depending on the distance they’ve put between themselves and Jean and Moblit’s presence to push him off the trail.

That startles Jean out of his daze, and he immediately stiffens and salutes Erwin smartly with a sharp nod, before turning on his heel and jettisoning away. 

Thankfully, it’s the time of the morning partway through breakfast when every nearly every soldier is in the mess hall, and they don’t run into anyone else.

By the time they hit the street, Erwin realizes he has no idea where they’re going. It appears Moblit is just as clueless, since they’re simply following Mike at this point, though it’s obvious his presence is still required since Erwin’s pheromones are only going to get stronger with each moment that passes. 

They walk until reaching the outskirts of the town proper, and then stop in front of a very small house. It’s set away from the street, almost a cottage of sorts, and obviously old.

“This house belonged to my sister,” Mike says unexpectedly, motioning toward the building. “She moved to Karanese with her husband, but they still haven’t sold it.” He shrugs slightly. “I keep an eye on it for them. No one will bother us here.”

Erwin stares at the cottage, something about the dark windows making his gut roil.

Moblit is matter of fact as he starts to explain what to expect. “The heat will last about a week. It’s best to have an alpha, or at least a beta.” He sounds like Hanji, save for the slight tremor of dread and horror in his voice as he refuses to meet Erwin’s eyes. 

“If I don’t?” Erwin questions.

Moblit looks up finally, and the expression on his face isn’t reassuring. “It’s hell,” he says bluntly. “Sometimes, if it’s bad enough, you’ll become ill.” He studies Erwin for a moment, the gears in his mind obviously turning. “But I don’t think that will happen, you’ve been on the stronger suppressants for so long. The heat might actually be dampened, but there’s no way of telling.”

Erwin sighs miserably, resigning himself to his fate, and also of apparently being a control experiment. “Moblit,” Mike cuts in, quiet up until this point, “report to Hanji. Tell her to bring anything that might help, and a change of clothes for the Commander, as soon as she can.”

“Yes, sir,” Moblit nods firmly, turning to dart off at an actual run back toward the barracks.

Erwin and Mike stand there awkwardly for a few moments, until Mike finally says, “This is a shit situation.”

“That it is,” Erwin agrees, relieved at Mike’s blunt declaration. “Shall we?”

Mike’s eyes widen as he stares at Erwin, and Erwin stares back at him in confusion; until he realizes Mike is sniffing at him, and he blanches.

“That’s not what I—”

Mike strides quickly past him toward the door, murmuring, “I know. You just smell…” he pauses as he bends to retrieve a key that’s stuck under a rock next to the steps.

“Good?” Erwin hazards, the word sounding ugly for some reason, like a perfumed noble at a ball.

“No,” Mike corrects thoughtfully, opening the door with a slight creak. Erwin follows, waiting for him to finish, sneezing slightly as he looks around the house curiously. It’s all one level, with a sitting room to the left, the kitchen to the right, and what Erwin assumes is the bedroom and bathroom toward the back.

“What, then?” Erwin finally prompts, knowing Mike has something else to say. “You’ve never held the truth back before.”

“Desperate,” Mike says curtly, his voice unemotional and flat. “Like listening to a wounded animal cry that you want to help.”

“That’s flattering,” Erwin quips, though he doesn’t doubt that’s exactly what he must smell like to an alpha, and even a beta. “And I’m not even in a…” he swallows hard, not wanting to say the word. But Erwin’s never been one to shirk the truth, so he says it anyway, “A full heat cycle.” 

Mike just shrugs slightly, turning to face Erwin and gesturing around. “We’ll take turns standing watch to make sure this passes without incident,” he says, all business even as Erwin feels himself becoming more lightheaded by the minute. He can already tell this is going to be bad. “We’ll tell everyone that you were called away on urgent business to the Capital. No one will question it.”

Much to his relief, Erwin knows that plan is relatively foolproof. However, Mike looks thoughtful for a moment, something occurring to him. 

“Erwin…” he starts, trailing off with a slight look of consternation, “there are a few people we can’t tell that, not for a week.”

Erwin frowns slightly, giving Mike some space from his pheromones which are obviously starting to get to the alpha as his nose twitches wildly he crosses his arms stiffly, before moving to open a window behind him.

“You’re right—no one will question it,” Erwin replies, confused now. “I’m called away all the time.”

He idly pokes his head into the room off the sitting room, and his assumption that it’s the bedroom is confirmed. He tries not to think about what he’ll be doing there, though.

“The bed is clean, left from my sister,” Mike assures him. “I’ll bring you some sheets later.”

There’s a short silence, and Erwin sighs slowly to himself; he already feels exhausted.

“Levi,” Mike finally states, the question there. “We can’t just tell Levi that you’re gone for a week.” 

“Levi…” Erwin trails off, hating the idea that he’ll need to tell Levi this. It’s not that he thinks he’d be judged, but over the years, Levi is one of the few other people who Erwin spends time with who doesn’t really give off much of his own biology. He takes the suppressants all the soldiers do, and Erwin’s never bothered asking him; doesn’t actually want to know.

They talk about everything from tea to expedition plans, sometimes even philosophy when Levi’s feeling generous and willing to indulge Erwin’s bookishness, but never about this.

“Levi won’t question it,” Erwin says weakly. “I don’t tell him everything I do before I do it.”

To that, Mike raises a skeptical eyebrow, though it’s a gesture that barely discernable under his mop of hair. “Maybe.” He replies with a shrug, something in his voice clearly indicating that he thinks Erwin is being delusional, but it’s not judgmental. “You know he won’t listen to me if you’re missing.”

Erwin sighs, rubbing a hand over his face. “I know.”

“You think he’ll judge you?” Mike finally asks, his voice cautious but open.

“Of course not,” Erwin replies. “But given that I’ll probably be drooling within the next twelve hours and begging to be knotted, that’s not how I’d like to go about sharing the information.”

Mike nods, looking sympathetic, but he doesn’t apologize for the bold question. It’s one thing about Mike that Erwin’s always liked—if his modus operandi could be summarized in two words, it’d be “no bullshit.”

“Not only that,” he adds, “but it’s going to take more than me, Hanji, and Moblit to be on watch twenty-four hours a day for a week.”

Erwin chuckles a little, imagining Levi’s reaction to the absurd situation. Knowing his captain, Levi would probably volunteer to watch for the entire week and try to stay awake for it.

Then again, knowing Levi and what he’s capable of, he might actually succeed.

“All right,” he nods. “Just tell him.”

“Do you want to do it yourself?” Mike asks, obviously doing his best to be as respectful as possible.

“I don’t think I’ll be able to.” Erwin’s gut twists, and suddenly, he feels like he’s been sucker punched as something pungent and powerful rises up into his nose.

Mike is staring at him, his pupils dilated somewhat, and Erwin realizes it’s a waft of pure _alpha,_ and damn if he doesn’t want it more than he’s ever wanted anything he can recall.

“Sorry,” Mike apologizes, stepping back again. “I think you’d better get settled.”

Erwin closes his eyes and inhales deeply, trying to clear his head. He knows the heat will come in spikes, that the worst times will be when he’s so crazed with the compulsion to be knotted and mate that he might actually lose his mind; he’s not there yet, though, and he hopes Moblit is right that it won’t reach the point of falling ill.

He nods, reconciling himself to his fate. Like the bedroom, the sitting room still has a small sofa and two battered chairs patterned in a hideous floral fabric, obviously left behind by Mike’s sister, big enough to at least relax and read a book. Erwin would like to think that he could simply ride out the heat by mind over matter, reading until he was past his own damned biology, but he knows that isn’t an option. That simply isn’t how it works, even if he manages to remain sane during the week.

“There are some books in the bedroom,” Mike offers weakly, but it makes Erwin smile a little. He forgets sometimes that Mike is his friend as well as comrade, a real friend, who knows Erwin behind his title. “I don’t know about my sister’s taste, but she’s smart, so you might like them.”

“Thank you,” Erwin replies, seating himself on the sofa.

“Hanji will probably come with Moblit,” Mike warns him.

“I’m sure Hanji has seen much worse than a repressed omega who forgot to take a pill,” Erwin quips wryly. “She studies human biology as much as Titan.”

It wouldn’t surprise Erwin one bit if Hanji is the type of beta who analyzes responses and pheromones during sex; it also wouldn’t surprise him if Moblit encouraged it.

He can’t say he’s not a little bit relieved that of all the people who this could happen in front of, one of the best scientists within the Walls is helping keep watch over him.

Mike gives a nod. “I’ll be outside. I’m sure they’ll be back soon with supplies.”

Erwin nods, running a hand through his hair as he looks around the room again; some dry witted part of his mind tells him he should ask Mike to remove anything that could be used as an implement that could be used to mimic sex, until he realizes that he’s only half-joking.

“Erwin?”

Erwin is startled out of his thoughts by Mike’s voice, especially because it’s hesitant, something he’s not used to.

“Yes?” Erwin asks expectantly, fixing his eyes on Mike, ignoring the flush that runs through his body as he gets a few tendrils of alpha scent. Mike smells good—like oiled leather and warmth, strong, solid.

Erwin shakes his head, chasing away the thoughts, resolving to breathe through his mouth. It probably doesn’t help, but it’s not as if he can do anything else.

“If you need…” Mike seems to search for the word, but then gives up, “help, I’d be willing…”

Erwin wants to express vehement outrage, but he knows Mike is completely serious, and it’s probably not the easiest thing to offer your Commander your alpha cock; so he just smiles tiredly and shakes his head. “Thank you, but no.”

Mike nods quickly, a slight flush in his cheeks, though Erwin’s sure it’s out of embarrassment at having to offer something that most people would see as undignified.

“Mike,” Erwin adds as Mike turns to walk out the door, “even if I beg, no.”

Mike nods in understanding, and he looks partially relieved, if not a bit worried.

*

As the day fades to night, Erwin grows more uncomfortable. There’s a hot, irritable prickle his skin, rather than a full-blown delirium, and he’s able to ignore it for now. 

The prickle grows worse, though, and when Hanji knocks at the door and Erwin bids her come inside where he’s sitting by lamplight, reading a book to distract himself, he must look worse for the wear because her eyes widen behind her glasses.

That, and he has to fight every screaming instinct in his body to fall at her feet and inhale every pheromone she has to offer; it’s disconcerting, especially since he’s still in his right mind, able to discern between the heat and his own thoughts. And Hanji’s not even an alpha; but she’s a _person_ with a _scent_ who can _touch_ him where he needs it and—

Erwin shuts out his thoughts. 

“Erwin,” she greets him calmly, despite the expression on her face, “I brought you some things.”

Moblit stands behind her, watching closely, looking mildly nervous as he always does; and Erwin is hit with a sudden sharp sorrow that kicks him in the gut, makes his chest ache, at the obvious chemistry between them. Because they’re mates.

_And he wants a mate, needs someone to fill up the empty space that’s suddenly appeared in his body, make the intense loneliness go away, chase him out of the void._

He rubs his hands over his face, trying desperately to clear his thoughts, before looking up.

“How are you?”

He inhales, trying to center himself the same way he did as a trainee— _one, two, three, breathe Smith, failure isn’t an option_ —and he wipes the sweat off his feverish face with the back of his hand.

“Increasingly worse.”

She offers him an assessing look, studying his face and body, looking around the room to see if anything is out of place, like a rabid animal being kept in accommodations that aren’t designed to hold them. Moblit just looks deeply sympathetic.

Hanji puts down a box Erwin just now notices, and she backs away toward the door. “I’m on watch to relieve Mike,” she explains. “I’ll be outside. Moblit will explain what’s in the box.”

“What?” comes Moblit’s surprised voice, as if he’s not expecting to be the one put on the spot.

Hanji fixes him with a meaningful look, and after a moment, understanding flashes through Moblit’s eyes as he finally seems to notice Erwin’s hungry eyes on Hanji.

“I apologize,” Erwin says softly as Hanji takes her leave and he realizes how obvious his attention had been. That, and he knows he’s putting out waves of scent now, probably desperate and odorous and clamoring for attention the way Mike had described.

“It’s not your fault,” Moblit replies, his voice firm. “You’re handling this much better than anyone else I’ve ever seen.”

That catches Erwin’s attention, and he looks over at Moblit in interest. “Others?”

“No one in the military,” Moblit says simply, obviously not in the mood to elaborate. As if suddenly realizing his informality, he straightens his posture and pushes the box toward Erwin.

“These help with omega heats,” he explains as Erwin peers into the box hesitantly. The first thing he pulls out are a few syringes and vials.

“These are sedatives,” he says, setting them gingerly on the table in front of the sofa. “They’ll temporarily reduce panic and desperation, but save those for the worst moments. They’ll do the job, but you’ll feel even worse in your head.” He hesitates, but then keeps his voice clinical. “You’ll stop trying to put things inside yourself, but it will feel like the world is ending.”

Erwin coughs, hoping it won’t come to that, but he nods calmly.

The next few items are oblong glass objects, some with flanged ends and some with what could only be described as a handhold, and it’s clear what those are for without any detailed explanation. 

Moblit clears his throat and continues.

“There’s also rations in the bottom, which will be easier to keep down than regular food, especially if you start feeling feverish.”

“You’ve gone through this?” Erwin asks bluntly, gingerly replacing the sex toys and vials into the box.

“Yes, only once,” Moblit admits, but it’s an easy admission, as if he’d rather be talking about his own troubles than explaining what a butt plug is to the Commander of the Survey Corps. Erwin can’t really blame him either. “But…” he frowns mildly, looking almost guilty, “I had someone with me.”

He means Hanji, and it becomes apparent from the expression on Moblit’s face that Erwin’s lack of a Hanji isn’t something to be taken lightly.

“Moblit,” Erwin says, his voice serious and solemn enough to make Moblit’s eyes widen, “in your personal and scientific opinion, is it necessary to have a heat mate? Hanji has said it’s not in the past.”

Moblit hesitates, obviously torn between some opinion of his that doesn’t match with Hanji’s, but one look at Erwin seems to make up his mind.

“I don’t recommend it,” he finally answers diplomatically, eyes darting to the door as if he feels traitorous admitting dissent. He meets Erwin’s eyes with a meaningful expression, his brow slightly creased. “No, it’s not necessary. Our research conclusively proves, at least in all the cases sampled, that no omega deaths have resulted from completing a heat unmated.”

Erwin waits, knowing there’s more; Moblit bites his lip unconsciously, but continues.

“But it’s different when you’re an omega,” he finally admits, shaking his head as if a great weight has been lifted from his shoulders. “If you talk to an omega, research doesn’t matter.” He shakes his head, not meeting Erwin’s eyes. “It’s pure torture, Commander. I think I’d rather be eaten by a Titan.”

Erwin would want to rebuke a soldier for saying such a thing, but given that Moblit is deadly serious and he’s Hanji’s mate, he takes the grave statement for what it is.

“If it comes to that—” Erwin starts, but Moblit interjects.

“Hanji is willing to assist you,” he says, “she already told me.”

The thought of Hanji helping him through his heat doesn’t appeal to Erwin any more than Mike, but given what Moblit has told him, he’s now almost regretful he didn’t tell Mike something else. Then again, Mike, despite his outward taciturnity, is a complicated person; Erwin’s not sure how things would be after, especially since they’re friends.

Hanji, on the other hand, would be clinically scientific about it, maybe even consider it an experiment. 

He finally nods. “Alright.”

“Commander, Hanji’s a beta,” Moblit hazards, meeting Erwin’s eyes. “Going through my heat without an alpha was difficult, but we’re mated. If you’re unmated…”

“My body most likely won’t quiet down unless I have an alpha,” Erwin finishes, trying not to groan as his skin starts to prickle again. It’s going to be a long night.

“What about Captain Ackerman?” Moblit ever so helpfully suggests.

Erwin blanches before he can hide his expression, and Moblit shrinks back slightly, an apology already on his lips as Erwin holds up his hand. It’s not an unreasonable suggestion, given that Levi and he work so closely together on everything, and their trust is evident.

“I’m not sure of Levi’s biology,” he says carefully. “And it might be too late to ask him anyway.”

Moblit just studies him for a moment, head cocked to the side in surprise. “Captain Ackerman is an alpha,” he says, obviously taken aback that Erwin’s didn’t know. “It’s not a secret—everyone knows. He doesn’t try to hide it, even though he’s on suppressants like everyone else.”

Erwin shuts his mouth; truth be told, although he never spent much time thinking about Levi’s nature in that way, he always privately either assumed omega or beta. Omega, due to Levi’s smaller stature, or maybe a beta with genes that didn’t effect him in any particularly dramatic way. Erwin doubts that Levi even knows anyone who’s in his genetic pool besides his mother, whom he’s mentioned in passing precisely twice in all the years Erwin and he have known each other.

“Very well,” he finally sighs. “If Levi is agreeable to it, I give my consent now, before I…” He almost says ‘lose my mind,’ but decides to re-phrase, if only for his own sanity. “Before I’m in the throes of the heat. But only if it’s necessary. I’d prefer not to have anyone with me if possible.”

Moblit nods in understanding, and Erwin is suddenly eager for him to leave so he can get ready for the mental fight of a lifetime. 

“Good night, Commander,” Moblit says, standing and saluting. “If you need anything, Hanji is outside. I take next watch at six a.m.”

“Is Levi in the rotation?” Erwin asks in dread.

“He is,” Moblit confirms. “He’s been briefed on the situation.” 

Erwin appreciates Moblit’s formal tone, but he’s curious about what Levi’s reaction was, especially given that it’s just been revealed Erwin is an omega.

The man who recruited Levi from the Underground, forced him to join the Corps, and was almost killed by his very hand on a rainy day of carnage, is an omega. Erwin has to admit he’s a bit curious as to why Levi isn’t here yet to assess the situation to his own satisfaction, as Levi is wont to do if he’s not under orders from Erwin himself.

“Hanji refused to tell him where you were until you were settled,” Moblit continues, as if reading Erwin’s mind. 

That earns a small smile from Erwin; he can only imagine how that conversation had gone.

“Is anything in Hanji’s lab broken?”

“Only one beaker,” Moblit replies, his voice light now, too, “and she dropped it because Captain Ackerman slammed the door behind him.” 

Moblit pauses, studying Erwin for a moment. “If he wants to see you before his watch starts?” He knows very well that Erwin doesn’t want anyone to see him when the heat spikes, desperate to be fucked and out of his mind with heat haze.

But Erwin knows that Hanji and Moblit—and possibly a small army of Titans—couldn’t stop Levi if he was set on entering the house. Erwin chuckles slightly. “I don’t think that’s a question I can answer. If he wants to come, let him come.”

“There are linens here,” Moblit offers, picking up a sack from next to the door that he must have forgotten about, most likely fixated on the fact he was carrying a box of sex toys to his Commander, “if you want to make the bed.”

“Thank you, Moblit,” Erwin replies, his voice tired to even his own ears. “For everything. It’s much appreciated.”

Moblit flushes a bit at the praise, but he nods, salutes, and then ducks out the door, closing it softly behind him. There are the sound of hushed voice—most likely Moblit giving Hanji an update on their conversation—before footsteps walking away.

Already, the room seems painfully empty, even though Erwin knows Hanji is right outside the door. He shivers a bit.

In the suffocating quiet that follows, Erwin decides the best thing to do is make the bed, and try to get some sleep.

*

The first day is hell.

It starts in the middle of the night, pitch black outside that Erwin can’t even begin to guess what time it is, when he wakes up in what can only be described as absolute hysteria.

Everything is hot, searing, and he feels desperate, throwing his head back and trying to breathe; but all thoughts of anything rational or familiar fade, until all he can do is stroke himself in the most unsatisfying act of masturbation he can ever remember.

Erwin jerks off like anyone else. He’s never had a particularly voracious sexual appetite, especially for anyone trying to hide an omega scent, but orgasms are a nice way to relieve tension, are uncomplicated.

This is different. This is him rutting up into his hand with tears forming at the corners of his eyes, his back arching sharply off the squeaky bed and thrusting into the tight circle of his fingers until he’s sore, seeking something desperately that he’s not finding. His skin no longer prickles, but hurts, and his eyes roll back in his head as he gives up even after he comes.

He’s soaked in sweat—must have been before he even woke up—and he whimpers, since there’s no one there to hear him. He’s not sure whether this is a good or bad thing, and somewhere Moblit’s words echo in his head.

One thing that actually makes him flush is the realization that his ass is slick—the words _self lubricating_ ring through his head, more than words on a page in a book now—and it’s so embarrassing he can do nothing else except close his eyes and force himself to lie still. He almost feels like he wants to punish himself, the bile of self-hatred rising up even though he knows it’s no fault of his own, that if he asked for assistance, he wouldn’t be judged by those offering.

But he bites his lip, draws blood until he tastes the sharp metallic tang, to ground himself.

He makes a concession and slides his fingers down, slowly, feeling mortified by his own eagerness— _inside yes, yes there_ —as he slips two fingers at once inside himself.

For just a moment, the fury of need cools as he starts to fuck himself, easily fitting three as he ruts down on them and starts to stroke himself for a second time with his cock already erect again. 

This time, the orgasm is less empty, but more lonely. He’s keenly aware that his fingers are his own, that the hand on his dick is his own, that he’s alone in a bed, alone in a house, so alone.

The thought is enough to make him want to cry, the same way he had after his father died, in private, profound unarticulated grief.

He orgasms twice more, finally gives in and retrieves one of the glass dildos and fucks himself with it until he’s too tired to go again, before falling into a fitful sleep.

*

The night is long, but he does sleep, and there’s not another spike.

In fact, he’s well enough the next morning to bathe and eat some of the food in the box, even though they’re just standard military rations. Practical, unindulgent—exactly the type of feelings Erwin needs right now. He’s calm enough now to at least pull on a pair of pants and glance out the front window.

It looks to be about noon, but he starts when a breeze filters through the open window, all the smells of the outside world there with it.

He sniffs at the air, and then something much more distinct than dust and sunshine hit his nose, familiar and immovable, and he realizes it’s Levi’s turn on watch.

The scent is comforting for now, not alpha yet, so much as simply Levi. Erwin knows that will change very soon and he needs to get away from the window, but he can’t help but breathe it in.

Now that he thinks about it, though, and especially in this state where Erwin can pick up on practically every scent around him, it’s more than obvious that Levi is very much an alpha. The way Erwin’s heart flips over in a purely biological response is testament to that.

Levi smells like clean things—mint tea, soap, fresh air—but underneath there’s iron, the tang of cold metal. 

It’s achingly familiar, and suddenly, an immense sense of _want_ slams into Erwin hard from all sides. It feels like the first time ODM wires tugged at his body as a trainee, the reality of how a well-placed grappling anchor hooked to a tree could be foiled by a poorly placed one and send him careening out of control, a terrifying velocity trying to tear him apart, a potential fatal fall to the ground.

He stumbles away from the window and clumsily makes it to the bedroom, shutting the door soundly behind him; but the smell is still there.

Mint, soap, air— _Levi_ —and then Erwin’s got his hand down his pants, jerking himself off before he can even think it through, slowing down his strokes as he sinks to the floor, back pressed to the wall as he fucks his hand; he lets his head fall back as he moans, not caring whether he’s heard.

He comes hard, the smell in his nose, and although some part of him that’s still present and sane gapes at the thought, the idea of going outside, yanking that door open and simply groveling at Levi’s feet, kissing his ankles and shins and thighs, has Erwin hard again in seconds.

Then, it’s the real life realization of Levi as an alpha for the first time that sends him into another downward spiral of lust, more desperate than the last, since he pictures Levi’s cock erect, hard for him, ready to knot him, to be inside and have Levi pressed against him everywhere.

Levi, who he trusts, who smells like tea, who has seen him in his worst moments and for whatever reason, follows Erwin’s orders like a shadow, complemented by curt, sharp-tongued observations.

“Fuck,” Erwin whines as he comes again, “Levi…” It almost hurts, and although he distantly aware that he’s experiencing another heat spike that was probably set off by Levi’s scent, he lets himself bask in it. It’s more comfortable than thinking about how alone he is, how he has no one.

Levi is here, and even though he’s outside, behind the closed door, he’s still _here_.

After that, it takes Erwin hours to calm down as he waits for the fervor to abate; but it does eventually, like a knife pressed tight against his throat that’s slowly being drawn away in excruciatingly small increments, but no longer suffocating.

He even manages to lie down long enough to read a few pages of a book to distract himself, and uses the opportunity to remind himself of who he is, where he is, what this is. It’s been one day, and although he has six to go, the reprieve is enough to lift his spirits at least a bit.

If every day will be like today, he knows he can ride it out and bear it; vows never to forget those fucking heat suppressants again.

He’s even well enough to change the sweaty, come-stained sheets (Moblit had the foresight to include at least a few sets), wash his face, and settle into the bed with renewed determination. He slowly drifts off to sleep, hoping that the next spike won’t be worse. Maybe Moblit and Hanji were right, that the strength of the suppressants he’s been taking all these years have dulled his natural heats permanently.

He can only hope, and desperately tells himself to sleep through the night; begs his body to grant him this one small favor.

*

Erwin wakes up to screams; it’s the first thing that registers in his mind.

The next, is that every single inch of him _hurts_ , like a glowing metal brand being pressed against his skin over and over, his gut wound tight with some horrific ache. It feels like he’s drowning in agony, and all he can do is moan, barely able to move.

He knows he has a fever now, that it’s worse than they thought it’d be; he’s not sure what direction is up or down, where he is, what time it is. He feels so desperately alone behind the closed door of the bedroom that he starts to wonder if he died and has finally made it to hell—if this is hell, because he would definitely believe it.

In some hazy part of his brain that’s happy to connect the knowledge with the current situation to drive him further into insanity, he realizes that it’s his body screaming to be knotted, desperate for an alpha; he’s not even sure it would feel good at this point. It’s just _needed_ and he feels like a wounded animal, calling out for help, exactly as Mike described.

By sheer will power, he manages to fumble with his hands to reach down and try to finger himself, stroke his cock, but it’s akin to telling a drowning man that he can breathe in water if it will make him feel better, since it’s really air that’s needed.

He doesn’t notice the door opening at first, but when he does, he can barely open his eyes or see beyond the tears that have formed there.

“Erwin.” He notes the voice is calm, shockingly so, but it’s the smell that gets him, drives Erwin over the precipice into complete desperation.

He claws at the source of the voice—an alpha, someone who can help him, who can _save_ him—and he whimpers, hoping that it will coax the dominant to knot him. He needs it so badly.

“Erwin, can you hear me?”

The alpha sits down on the edge of the bed—that’s all he is, _the alpha_ —and Erwin grabs onto him, squeezing anything he can reach.

If he thought the cramps were bad, then it’s nothing compared to the feeling of the alpha jerking away.

“I can’t,” Erwin groans, unsure of what he’s even trying to say.

Then, the alpha is back, and there’s a cool cloth pressed against his forehead—that feels good, but what feels better is the alpha’s weight next to him, his touch as fingertips skitter over Erwin’s forehead, the smell filling his nose, rich and heady and perfect.

“Will it help if I use the glass thing?” The question is calm, and it just makes Erwin feel even more hysterical.

All he can do is hope desperately that if he makes himself smaller, more retiring and submissive, this alpha will decide he’s worthy of attention.

Then, his leg is being hitched up and he’s rolled onto his side, and he groans out, “Yes, please, yes…”

Something that is most definitely not a dick slowly pushes into him, but it provides some relief in combination with the strong scent billowing off the alpha in waves—evidence that’s much more reassuring about how much he wants Erwin than words ever could be. 

He knows, distantly, that he’s being fucked with one of the glass toys, slow and methodical, careful; he grabs his own leg desperately to spread himself more, and the toy goes faster, fucking him like he wants it. It slides easily with the lubrication and how open and ready he is, and the cramps finally abate as he reaches down to stroke his cock, coming almost immediately.

He can feel the toy starting to slide out, and he keens. “No,” he begs, “no, not yet.”

“Okay,” comes the same voice, the alpha’s voice, “relax.”

Erwin lets out what can only be described as a pathetic whimper, but follows the advice, and slides into a mercifully empty sleep, completely spent.

*

He wakes up to light, possibly the second day, but it could be the third at this point. It could be three years and Erwin wouldn’t know.

He smells: mint, soap, air.

Levi.

When he tentatively rolls over, something between relief and dread coiling in his stomach, he sees exactly what he expects.

Levi is lying behind him fully clothed, his hand pressed against Erwin’s hip; somehow, Erwin knows it’s not sentimental, but that he probably begged for the maintained contact.

Shame washes over him—this is his fault for not taking his damn suppressant, he’s finally fallen victim to his own omega body, he’s forced his Captain into a highly uncomfortable position—but he chases it away, knowing the heat is making him feel and think things that aren’t real.

But he will give credence to the fact that he wishes he never put Levi in this position.

He swallows hard as Levi stirs, and he knows he’s going to have to face this. Obviously Levi hasn’t fucked him, but Erwin can come up with some likely possibilities that are embarrassing to even consider.

“Good morning,” Levi says as Erwin rolls over to face him, shimmying back slightly to press himself against the wall and taking the sheets with him.

When he doesn’t say anything for a moment, Levi blinks, more awake, as he looks at Erwin and then rolls over slightly to check something on the table.

“Do you need me to…” he asks, eyes darting down to Erwin’s hidden lower half, and then back up. It looks like he’s almost not expecting an answer, and Erwin realizes that Levi thinks he’s still in a heat haze.

“I’m sorry,” is the first thing that manages to fall out of his mouth, and Levi rolls his eyes.

“There’s nothing to be sorry for,” he replies, obviously realizing that Erwin’s back in his right mind, as he sits up and stretches. Erwin pointedly avoids inhaling too deeply or watching the way Levi’s body moves, and he breathes through his mouth. “I knew what I was facing. I volunteered,” Levi says, as if it’s the most ordinary thing in the world.

He looks back over his shoulder at Erwin, suddenly uneasy. “Moblit said that you consented to it, if you needed…” he trails off, looking almost embarrassed as he finishes, “an alpha.”

“I did,” Erwin nods, closing his eyes and slipping further under the sheets. He realizes now how sore his ass is, how raw his cock feels. He has no idea how many times Levi had to fuck him last night with that glass toy, but he can bet it was more than a few.

The embarrassing part, though, isn’t that it happened; it’s how Levi is looking at him now, poorly hidden concern and worry in his eyes.

Erwin feels the need rise up again like bile, a burst of desperate pheromones pouring off of him even he can smell as he fights the urge to curl around Levi so he won’t leave, to keep him here. It’s not a spike, but a sudden intense fear now that Levi’s not touching him.

“You don’t have to fight,” Levi says, his voice soft and knowing as he slides back into the bed to lie down, giving Erwin the choice of whether to move forward.

“Don’t leave,” Erwin breathes out, staring hard at anywhere except Levi’s face.

“I’m not going to leave.” His voice is hard and resolute, but he reaches out to touch Erwin’s hip again. “I’ll be with you until it’s over.”

“You can smell it, can’t you?” Erwin asks, shaking his head. He knows now what is must be like for people who don’t take a suppressant, constantly advertising every thought and emotion without saying a single word. It’s horrifying.

“Yeah,” Levi confirms, unflinchingly honest.

“Mike said it smelled like a wounded animal crying for help,” Erwin says dryly, shaking his head.

“That’s accurate,” Levi nods slowly in agreement, but he frowns, thin eyebrows drawing together. “But you’re not a wounded animal. You’re just caught in a shitty situation.”

“It’s my fault,” Erwin sighs, wanting to confess his own guilt before it eats him alive, since he really is the reason Levi is here. “I forgot to take my suppressants last week.”

“You mean when you didn’t leave your office for two days?” Levi’s voice gives nothing away, so Erwin just shrugs. 

“Yes.”

“If I’d known you had to take them every week,” Levi says simply, “I would have reminded you.” 

He just stares at Erwin, and Erwin stares back; they don’t break eye contact for an almost unbearably long time, until Erwin cracks first.

“No one knew what I was until this week,” he says quietly, wondering now why he didn’t tell Levi a long time ago. “Only Hanji, since she gives me the suppressants.”

“I already knew.”

That does throw Erwin for a loop, and he opens his mouth to speak, before shutting it again. “What?”

However, before the conversation can continue, he feels that hated heat spark through him, from the tips of his toes up into his cock.

An unhappy noise escapes his throat, and he tightens his jaw, determined to ride it out.

“Heat?” Levi asks, intelligent gray eyes glancing down to inventory the situation.

Erwin nods, scowling, and Levi sidles up next to without hesitation; Levi’s scent envelopes both of them, and Erwin can’t help the way he immediately curls around the alpha. In some way, it must look comical, since Levi is a good deal smaller than him; but Levi is unfazed, sitting up to let Erwin’s lay his head in his lap.

“Are you too sore?” Levi asks, smoothing Erwin’s hair away from his face in a surprisingly tender gesture.

Erwin’s suspicions are confirmed them—he was fucked a lot the night before.

“Use your fingers,” he asks, trying to keep his voice diplomatic and nearly succeeding. It’s certainly a step up from the horrific pain he’d been in the night before. The “please” slips in somewhere, but he’s already being turned over onto his stomach, his legs nudged apart, and then Levi’s finger circles his hole.

It might be an embarrassing position with anyone else, but with Levi, for the first time, it actually feels _good_ as he slips his finger inside.

Erwin moans, rutting into the mattress harshly; it squeaks, and Levi moves his finger in and out of Erwin’s body in rhythm, murmuring soft encouragements.

He adds another, which Erwin takes easily, and then finally there are three fingers fucking him, and Erwin orgasms with a cry, pushing back against the pressure. The sensation is more satisfying this time, makes him feel more at ease, floating in a blissful feeling of relief as Levi pulls his fingers out.

“I’ll be right back,” he says, and then waits until Erwin turns his head nervously, but nods firmly in resolution. The lingering pleasure of the first halfway decent orgasm he’s had in a series of many empty orgasms makes him feel relaxed; he can stand to let Levi leave for a few minutes.

But the minute Levi disappears out the door and closes it behind him, Erwin feels panic rise in him. There’s the sound of footsteps creaking over the floor, but then they stop abruptly.

Levi opens the door quickly, meeting Erwin’s eyes. “You’re panicking,” he says calmly, and Erwin realizes again that he can’t hide anything, even if he tries. “Don’t push yourself.” He frowns, crossing the room to sit back down on the bed and touch Erwin’s shoulder.

Erwin turns onto his back, trying to slow the hammering of his heart, and Levi just sits there with him for a few beats of silence.

“I’m here to help you,” he says firmly, but then looks thoughtful before tapping Erwin’s shoulder absently. “Did you look down on me when I hurt my ankle?”

Erwin frowns; the thought of Levi being a pitiable object of derision because of an injury in the field is absurd. He knows the question is a set-up for some point about to be made, but it still bothers him.

“Of course not,” he replies, eyes inadvertently darting down to Levi’s ankle that’s still healing from his fight with the Female Titan.

“That injury was my fault,” Levi says objectively, never removing his hand from Erwin’s shoulder. “I made a mistake and landed wrong, and I fucked up my own leg.”

“It wasn’t your fault,” Erwin argues, troubled now by this assessment. “It was a bad landing under extreme duress. You’re the strongest—”

Levi waves him off, stopping him mid-sentence. “My point,” he interjects, “is that this isn’t your fault.” He scowls darkly at Erwin. “I hated having people bring me food and clucking like a bunch of worried hens.”

And suddenly, Erwin doesn’t feel so awful about needing Levi close, about his rising panic when Levi walks away, because Levi understands.

In a surprising gesture, he leans forward to press his forehead against Erwin’s quickly and then draw away; Erwin’s not sure if it’s a tactic to calm him down during the heat, or if it’s just Levi’s quiet way of showing affection. The truth is that Erwin will take either.

“Alright,” he finally agrees with a sigh. “Just… can you leave the door open?” He still feels foolish, but Levi nods seriously and retreats again, hazarding a glance back over his shoulder as Erwin watches him intently.

He’s quick, but Erwin feels more at ease with the door open since he can hear Levi—the sound of water rushing out of the hand pump in the kitchen, the click of a kettle, Levi muttering irritably over how long water takes to boil.

When he returns, he has two cups of tea, a basin of hot water, and a clean cloth; he offers the cloth to Erwin to clean the dried come off his stomach, having obviously washed his own hands during his sojourn into the rest of the house. The feeling of hot water on his skin is pleasant, and Erwin relaxes finally.

It’s mint tea, and Erwin inhales its scent along with Levi’s; the two intermingle, and provide a source of comfort so complete, it’s almost startling. 

They sip their tea quietly, enjoying what’s sure to be a short-lived peace; Levi’s nudged close enough on the edge of the bed to make sure he’s touching the edge of Erwin’s arm ever so slightly, aware of what’s transpiring.

“You brought tea with you?” Erwin finally asks, amused.

Levi raises an eyebrow and nods. “Of course.” He studies Erwin for a moment, keen eyes darting across his face and down to his shoulders. “When was the last time you ate?” he asks suddenly with a slight frown.

Erwin blinks, but then doesn’t answer when he realizes he doesn’t actually know. “I think the first day,” he finally settles on. “I had some rations.”

Levi balks at him, and this time when he gets up, he’s faster, returning with some of the rations from the box. “Who gave you this shit?” he asks, offering Erwin some of the food. “Eat.”

Erwin doesn’t argue, sitting up to swallow the rations; he doesn’t realize how hungry he is until he’s tearing into the food, and a glass of water appears on the table. “Drink it,” Levi commands, his tone harboring no room for argument.

His body is more hungry than horny now, and Erwin guzzles it down.

“Wasn’t anyone watching you?” he mutters as Erwin lies back down, handing over the wax paper the rations were in and empty glass. 

“No one has come in,” Erwin remarks as Levi sets the glass and discarded wrapper on the bedside table. “I didn’t want them to.”

He pauses for a moment, studying Levi intently; Levi just stares back at him, unwilling to speak first. He does sit back down though, immediately placing his hand on Erwin’s waist, almost absentminded.

“Why did you come in?” he finally asks, quickly adding, “I’m glad you did.” He clears his throat, feeling self-conscious. “I needed it.”

Levi nods, apparently satisfied with Erwin’s level of honesty. “I could smell you,” he says bluntly. “And I heard you screaming.”

There’s something Erwin’s missing as Levi averts _his_ gaze now, and he wants to know what it is before the heat hits him again and addles his brain.

“And?”

Levi looks back at him, cocking his head to the side. “And what?”

“What were you going to say?”

Levi sighs slightly, looking exhausted for the first time since Erwin woke up, and he shrugs slightly. “You were screaming my name.”

That admission does make Erwin cringe, wondering if he was calling out a name in his sleep, some residual dream climax relived from that afternoon when he first smelled Levi outside.

As if sensing his thoughts, Levi continues, “Not that way.” He swallows a little, his mouth tugging down at the edges with tension. “Like you were in a Titan’s mouth.”

He was calling for help. Erwin’s not sure whether to laugh or cry.

He doesn’t have to, though, as the heat takes hold of him and the mug in his hand shakes, spilling a bit of tea.

Levi takes it from him as Erwin inhales a shaky breath, sets it on the nightstand, and lies down next to him, guiding him to the bed.

“How do you want it?” he asks, his voice gentle but straightforward.

Erwin inhales deeply, closing his eyes, no longer ashamed of seeking out Levi’s scent, because Levi is here to help, to take care of him. And his captain knows what it’s like to feel helpless and angry.

“Fingers,” he says resolutely. 

Levi nods, pressing a kiss against Erwin’s collarbones as he slides his hand between his Commander’s legs.

This time, the orgasm feels good.

*

Levi doesn’t leave him for the next four days, lying in bed with him, sleeping next to him, fucking Erwin with fingers, toys, even his tongue at one point. 

That one leaves Erwin quivering, but he’d been so feverish with his need that he’d allowed it. He was surprised Levi was even willing to.

He had been lazily pressing his cock against the bed as Levi stroked his back, pressed against his side and close, but Erwin was too sore to take anything else in his ass regardless of the fact he was desperate for it.

“I’m going to use my tongue, and then a sedative so you can rest for a bit.” It had been very matter of fact, business as usual, as if Erwin and he were discussing expedition plans over a set of dry, boring maps.

Erwin had nodded, exhausted and panting; he wasn’t sure what to expect as he got onto his knees and pressed his chest to the bed, but the flick of Levi’s tongue wasn’t nearly as ephemeral as he expected. It was hot and wet, and Levi hadn’t been shy, pulling him open and pushing his tongue inside.

It was good enough that he came dry, a weak orgasm wrung from his exhausted body, but a relief all the same; he’d collapsed, eyes shut.

“C’mon,” Levi had said, his voice faint as Erwin started to fall asleep, “I’m going to inject this.”

“Mm,” Erwin had been vaguely aware of himself saying, “I can’t go again.”

Levi had said something he couldn’t hear and then there was a sharp prick in his arm, and he slipped into a blissful sleep.

It was the last thing he remembered before waking up to what he sees now: Levi, asleep, his face lax and looking young across from Erwin, breathing softly. At this point, Levi hasn’t bothered to keep distance between them, tangling their legs together. It’s the easiest point of contact to maintain touch.

Erwin is hazy, but he’s decently lucid as he inhales. Levi smells like the scent Erwin’s come to be intimately familiar with, something dominant and starkly clean. But now, he also smells like simply _Levi_ , no pheromones to scramble Erwin’s brain. 

Erwin realizes the heat is finally winding down, and he breathes in deeply, feeling a sense of relief settle over him.

The response causes Levi to stir, grumbling as his eyelashes flutter, but he doesn’t open his eyes. “What are you so happy about?”

Erwin smiles a little at his bedmate’s innate grumpy nature, and he laughs slightly. “I think the heat is finally starting to recede.”

That gets Levi to open his eyes, but his expression is unreadable; if Erwin could describe the emotion coming off him, though, it would be pensive.

“Are you afraid things will change?” Erwin guesses astutely, and Levi frowns.

“No.”

“Then what?”

Levi hesitates, glancing down, though his expression is thoughtful. “Ask me again in two days,” he finally settles on. Although Erwin wants to press, he can’t fault a man for needing more time to sort through his thoughts, whatever they are.

“Alright,” he replies agreeably, pleased that the heat haze hasn’t hit him like it usually does immediately upon waking up. He closes his eyes, but suddenly is very aware of how ripe Levi smells, probably covered in sweat and Erwin’s come; he’s surprised Levi has been able to tolerate it, though it’s not as if he’s had much of a choice.

Then, something occurs to him, and he opens his eyes to look over Levi.

Levi is staring at Erwin’s shoulder, obviously lost in thought, unaware of being watched, until Erwin taps him on the arm. “When was the last time you bathed?”

Levi’s eyebrows shoot up, and he looks genuinely taken aback; before he can take offense, though, Erwin shakes his head, echoing Levi’s words back at him about eating.

“You can go. I’ll be fine.”

Understanding shifts into Levi’s face, and he nods, pulling away to stand up. Much to Erwin’s relief, that pang of panic doesn’t hit him this time, and he even manages to sit up, too, wincing as his body protests. Everything hurts, but not in a prickly way; it’s a familiar way, a type of physical exhaustion from pushing his body to the limit. This is a type of pain he can handle by himself.

Levi studies him for a moment, sniffs the air a bit, but then nods curtly. He leaves the door open, and Erwin hears water running, being heated for a bath.

He lies back, breathing in deep, turning his head to push his nose into the pillow Levi’s been using. It smells like both Levi’s alpha scent, but also his hair, and a little sweat—all things Erwin finds he likes very much.

There are two empty cups on the side of the bed Levi hasn’t cleared yet, and he’s distracted when the smell of pleasure and relief hits him; he smiles a little, since it’s obvious that Levi’s sunk into the hot water.

The strange part is, though, Levi still hasn’t knotted him; it gives Erwin pause, wondering if perhaps Hanji and Moblit had been right after all. Maybe the suppressants Hanji had refined were so powerful, they’d successfully tamped down some Erwin’s traitorous biology. No doubt that the experience had been harrowing and awful, but Erwin has to wonder how much worse it could’ve been.

He falls asleep, lulled into a comfortable slumber with Levi’s contented pheromones drifting in from the next room; he’s vaguely aware of Levi lying down next to him again, murmuring something about scrubbing him raw when this is over, and then that craved point of contact again, a hand resting in the dip of his waist.

*

Erwin had assumed that the end of the heat cycle would decline gradually, taper off into a mild ending, at which point he could resume his normal, daily life. He would be Commander Smith, Levi would be Captain Ackerman; they’d sit in his office and drink tea together as Erwin puzzled over maps and reports, and Levi would remind him to eat and offer up snarky commentary when fundraiser balls in the Capital requested his presence.

And although Erwin and Levi had long been “Erwin and Levi” to each other, by first names, Erwin wouldn’t mind falling back into comfortable, defined roles, at least for a little while.

He’s not expecting to wake up drenched in sweat, Levi’s hand stroking his side and murmuring reassurances.

“Are you awake?” he asks softly, his entire body pressed up against Erwin’s back. “Erwin?”

Erwin groans a bit as he places where he is, and curls in on himself; the cramps are back, more powerful than even that first night when he was wracked with them.

But unlike that first time, when he was alone, he feels Levi’s hand smooth down his belly to his hips, as if searching for an injury. The touch is soothing, at least on an intellectual level, but another wave of pain causes Erwin to shudder.

“Thought this part was over,” he manages to grit out. He no longer feels humiliated; just tired and unraveled, wanting nothing more than to sleep for a single night all the way through.

Levi immediately reaches down to push two fingers inside of him, knowing this routine well by this point, and although Erwin grinds back on them, he whines.

“What do you need?” he whispers, pressing his forehead against Erwin’s back. He sounds troubled, his voice colored with worry.

“I…” He knows exactly what he needs, but this time, there’s someone here who can provide it. “I need you inside.” He starts to pant now, the heat taking over once he’s admitted it; it’s like an avalanche of need. “I need you to knot me, need you inside…” His voice sounds frantic to his own ears, but he’s no longer listening to himself; he just needs that cock inside, that knot inside, needs it worse than anything he can remember. He can feel himself sinking into that hysteria again, a desperate haze of confusion and hurt. 

But then, Levi is there, running a soothing hand up Erwin’s ribs, then up over his shoulder to smooth his hair; excruciatingly kind, the way that Erwin knows Levi can be in moments of extreme privacy.

“Okay,” he murmurs, and the click of his belt as he pushes off his pants and underwear, the warmth of his cock and thighs pressed against Erwin’s backside, is something that Erwin knows he will be forever grateful for. Levi’s shirt comes off, too until they’re skin to skin; somehow, it’s both too intimate, but also a relief, not being fucked like an animal in need of wound care. 

Erwin feels fingers spreading him open, the touch familiar and reassuring, but then there’s a blunt sensation that makes his toes curl as Levi pushes his cock experimentally against Erwin’s hole. 

“Breathe,” he says softly, and slowly pushes in, a pleasure blooming in Erwin’s gut as he pulls his leg up to open himself up, moaning.

“Good,” Levi murmurs, his voice tender, but somehow not placating, not the way anyone else’s would be in this situation. He’s treating Erwin as delicate, but it’s acceptable, because Erwin _feels_ delicate, and he knows Levi can smell it, knows that he wouldn’t be treated delicately unless he wanted it and needed it. “You feel good,” he says, slowly starting to thrust. “Is this what you need?”

“Yeah,” Erwin moans, reaching up to clutch at Levi’s hand desperately, seeking a ballast. Levi wraps strong fingers around Erwin’s hand, welcoming the touch, holding him close and keeping him sane. 

He likes the way that Levi seems to lose himself then, the way he pistons his hips, as if mindlessly driving toward some goal they’re both tripping over their own feet to reach. The smack of skin and rasp of breath are only noises in the room, and Erwin moans long and low, desperate to feel Levi knot him, to fill that void that’s plagued him since the first day he arrived here.

“Give it to me,” Levi whispers as he reaches down to stroke Erwin’s cock, his hand strong and sure, coaxing. “C’mon, come for me while I fuck you.”

Erwin’s voice is twisted and almost foreign to his own ears as he screams and comes violently, his entire body shaking with it as Levi milks the first orgasm out of him, murmuring praise and kissing at his back.

But then, Erwin shivers as he feels the fingers of Levi’s free hand brush against his scent gland, whining as he rocks his hips into Erwin, the instinctual alpha in him finally butting up against his incredible self-control.

“Fuck,” he murmurs, panting against Erwin’s shoulder blades, but pulls his hand away from Erwin’s neck. His want is practically tangible, the urge to mark Erwin as his, mix up their pheromones and scents in a place of no return.

But he doesn’t. He grips Erwin’s hand harder than Erwin’s gripping his, and comes.

Levi’s scent blooms around them, and Erwin can feel the knot inside him; he feels safer than he can ever remember, the outside world blotted out as he floats in a heady miasma of everything that is Levi, every beautiful thing that Levi has ever given him, rushing through his nose and body.

He means to say something—he really does, he wants to pant out Levi’s name and say foolish things into the exquisite privacy of this moment—but instead, he passes out as Levi holds him close, strong and dominant.

*

The next time he wakes up, it’s morning, and he feels fatigue bone deep. Levi’s knotted inside him—they fucked innumerable times the night before, to the point Erwin lost track—but he’s breathing evenly, and he obviously knows Erwin’s awake now.

“You okay?” he asks uncertainly, smoothing his hand down to Erwin’s hip.

“I’m…” Erwin isn’t sure what to say. 

The sun is out again, and for the first time, Erwin feels clearheaded. Maybe it’s the relief of _finally_ being knotted, or the end of the heat, but he feels more like himself than he has in days.

“Yes,” he finally answers.

“The knot is going down,” Levi replies, his voice even and resolute.

“How many times did we…” Erwin trails off, his memory a bit patchy now, just a series of hazy moments with Levi’s cock inside of him at the center of each one.

“Several.”

“Did you…”

“Every time.”

“Thank you,” he says softly, and finally, Levi’s knot goes down and he pulls out with a wet sound. It’s an empty feeling, but not like that terrible loneliness that gnawed at Erwin down to the proverbial bone before. 

And just like that, Levi is up and getting dressed; granted, when Erwin rolls over to look at him, he looks exhausted, but he’s standing.

“The heat’s over,” he says, pulling his shirt over his shoulders and buttoning it hastily. Erwin senses he wants to get out of the house, and really, he can’t blame Levi, whatever his reasons are.

“How do you know?”

“I can smell it.”

And Erwin knows it, too.

They look at each other for a moment, eyes locked, until Levi looks away. “Mike’s outside. I’ll tell him to help you back to the barracks when you’re ready.”

Erwin hums his thanks, suddenly feeling self-conscious of his nakedness for the first time in days as he pulls the sheet up over himself.

“Erwin…” Levi says, his voice soft.

“Yes?” He stares openly now, wanting Levi to say _something_ , because Erwin can still feel deft fingers brushing against his scent gland, can still smell mint, can still sense that calm that Levi emanates even without the need created by a heat.

Levi raises a critical eyebrow, and says, “Don’t forget your fucking suppressants.”

Erwin smiles a little at the venom-laced jibe, but he knows it’s not intended to be taken as an angry rebuke, so much as Levi’s way of brusquely telling him to take care of himself.

Levi’s lips quirk minutely, and he nods; then, he’s gone, the door opening and shutting.

This time when Erwin feels lonely, it’s marrow deep, but it’s not the heat.

*

Things get back to normal surprisingly quickly after that. No one questions Erwin’s absence, and Jean passes him in the hallway without incident. Erwin notices that he does tend to let his eyes linger on Moblit still, but it doesn’t seem to be with intent, just slight fascination.

Erwin can’t blame him; he knows now what it’s like to be in biology’s cruel clutches.

Mike comes and greets him, salutes stiffly, until Erwin thanks him and gives him an update about expedition funding. Everything is perfectly normal, and Mike looks relieved. He pats Erwin on the shoulder twice in a fraternal gesture, Mike’s version of a hug. “Commander,” he says sharply with a smart salute before leaving’s Erwin’s office. 

Erwin has to smile since Mike hasn’t used his formal title in private for years; he appreciates the gesture.

Hanji comes by with Moblit to deliver her findings of the effects of the strong suppressant on Erwin (model omega subject, apparently), which involves a half hour oration in painful detail, until, mercifully, Moblit comes up with a reason for them to leave. 

Levi, on the other hand, isn’t seen for days.

Erwin forces himself to be calm about it on the first day, assuming perhaps the other man needs some time to think. On the second day, Erwin becomes anxious, unable to concentrate on any of the reports he has in front of him because Levi’s not there in his customary chair, sipping tea and looking over his own paperwork.

The third day, Erwin feels an emptiness that he recognizes as irrational, and then he shuts all the feelings out, tamps them to the ground, attributing his own absurd emotions to the aftermath of going through a full heat.

Finally, Levi shows up on the fourth day, entering Erwin’s office as if nothing is different and complaining about a few cocksure cadets who also can’t manage the simplest of obstacle courses.

Erwin just sits there, relieved to see him, unspeaking. 

Levi keeps talking, sets a cup of tea down on Erwin’s desk—he notes that it’s not mint—and settles into his usual chair, nimbly snatching the field reports Erwin always pushes until last from the corner of his desk.

Then, he quiets, reading the report as he sips his tea; for a moment, Erwin wonders if anything from the past two weeks even happened, but he’s suddenly keenly aware of Levi’s scent.

It’s not the same sensation as being in heat, where he could practically read Levi’s moods from a room away, and vice versa. Now, Levi doesn’t smell like anything in particular, but if Erwin really looks for it, he can detect the faint scent of alpha.

Then again, Levi isn’t on the potent suppressants that Erwin is.

Without looking up, Levi flips the page on the report, and says, “I can’t smell you.”

Erwin settles back in his chair, satisfied, and feels at ease; he takes a sip of his tea, but he can’t shake the feeling that something is still wrong. The tea doesn’t taste right, for one thing, since it’s not mint.

And Levi is mint—a fact he now knows, that he can’t let go of.

“New flavor?”

Levi barely spares him a glance. “I’m tired of peppermint.”

Erwin swallows hard, but he nods. “Change is good.”

*

That night, Erwin can’t sleep, and he doesn’t know why.

He’s in his own rooms at the barracks, a comforting and familiar place, unlike his house in Karanese he rarely ventures to. His bed seems empty, the room seems empty, even his body seems empty.

The strange part is that it’s not the same feeling of a void he’d felt during heat, nor is it some uncanny absence of a mate. Levi didn’t mark him, didn’t blend their scents, didn’t do any of the things a mate does; he assisted Erwin in his hour of need, gave everything to ensure his survival and comfort.

Erwin gets up out of bed, sighing as he pours himself a glass of water from the pitcher he keeps on the table and ponders the situation at hand.

It’s frustrating to dissect, uncannily similar to how the heat had addled his mind; only this time, he has his mental capacities fully intact, yet still finds himself confused.

Levi is acting normal and seems perfectly content to fall back into their regular routine that existed well before any alpha or omega biology was ever revealed. He doesn’t act any different except changing the tea flavor, and maybe once in a while he averts his eyes when Erwin rolls his neck after a tiring day.

But that’s reasonable—an expected outcome of what they experienced—a thing that Levi hasn’t brought up, but also hasn’t denied. 

After a few sleepless nights, though, with shadows around his eyes he knows are obvious, Erwin cracks.

Levi still hasn’t been able to return to the field, so he busies himself with training exercises, occasionally giving the cadets “pointers” about how to improve their form if someone stares at him for too long, morbidly fascinated that “humanity’s strongest” is still recovering from an actual, human injury.

He shows up in Erwin’s office one afternoon, tired and sweaty from training, only the smell of his regular human body detectable now, a combination of sweat and soap.

“How’s your ankle?” Erwin asks cordially.

“Better,” Levi answers noncommittally, taking his usual seat across from Erwin’s desk, looking with interest at the papers scattered there. 

“New expedition?” he asks hopefully, which heartens Erwin a bit.

“No. Just death notices and letters from nobles asking for absurd things.”

Levi huffs and rolls his eyes. “Idiots.”

Erwin smiles a bit as he looks up to meet Levi’s eyes, and although he wants to stare for longer, he forces his gaze back down at the dull letter in front of him.

There’s a short silence as Levi bends over to undo his boots, obviously intending to remove his gear right there in the office, and Erwin draws the line.

It’s not even unusual; Levi has certainly disarmed himself many times here, stripped off boots that needed cleaning and straps that required oiling, comfortable in his pants and bare feet reading boring papers until the early hours of the morning, legs folded underneath of him as Erwin wrote and read on through morning.

Erwin can’t stand it anymore as Levi’s first boot comes off, and he looks up in surprise as Erwin pushes all the papers away and stares at him.

“What were you going to tell me?” Erwin asks sharply, unable to hold it in any longer. Maybe it’s the lack of sleep, or how the memory of Levi’s fingers pressing against his scent gland keeps popping up in torturous, waking dreams. 

“What?” Levi replies, genuinely confused and beginning to frown.

Erwin inhales slowly, exhales just as slowly. “During that week,” he says diplomatically, “you said you already knew what I was.”

Levi’s face goes blank, and he immediately starts to pull his boot back on, obviously intending to leave, and Erwin knows he’s stumbled onto something important; he just has no idea what it is.

“How?” he asks, his voice even and firm. “Don’t leave until you answer.”

Anger flashes in Levi’s face, but Erwin allows those gray eyes to piece him apart, deconstruct him, just as he had in that come-stained bed day after day. 

“You know my last name,” Levi finally answers, crossing his arms over his chest as he finishes pulling his boot back on, clearly ready to retreat. “I share it with Mikasa, Eren Jaeger’s shadow, the one who was valued at the strength of a hundred soldiers.”

Erwin raises his eyebrows, not expecting the conversation to go this way; he sits, hoping Levi will do the same.

He doesn’t, of course, still glaring. But when Erwin nods, leaning forward with a tired sigh, Levi relaxes a bit.

“Ackerman,” Erwin states, leaning his chin in his hand thoughtfully. “Is that a name I should know outside my best soldiers?”

Levi snorts, and it’s condescending; it’s the sound of that thug in the Underground Erwin met years ago, and he just smiles slightly.

The most amazing thing about Levi, that Erwin has realized over the years, is that he hasn’t actually changed that much; it’s Erwin that’s changed, the Survey Corps, humanity’s last bastion of civilization since Wall Maria fell.

Levi Ackerman is still the lethal, acrobatic smart ass he always was, kind to the people he chooses, painfully empathetic to those under his command—he’s just gotten a bit better at not biting back at people he doesn’t trust.

Erwin, on the other hand, has grown more cynical; and for a moment that isn’t the first time, he marvels at Levi.

“You might,” Levi replies seriously. “If you hear the name, be careful.”

“Why?”

Levi hesitates, but it’s more a thoughtful silence than hesitance. “I had an uncle,” he finally blurts out, his voice guarded in a way Erwin hasn’t heard in a long time. “He was my mother’s brother, from what I could tell, but I haven’t seen him since I was eleven.”

Erwin mind starts to reel, but he keeps it to himself, forcing quiet in his brain until Levi finishes. He just nods in response to Levi’s careful words.

“I’ll keep that in mind,” he replies diplomatically, already preparing to trawl reports or archives he can find for the Ackerman surname. “But...”

Levi sighs now, sounding exhausted, but he doesn’t shy away. “Mikasa is Eren’s shadow. Have you ever wondered why such a talented soldier hangs around such a weak kid?”

“I understand their story is complicated.”

Levi rolls his eyes.

Erwin’s eyebrows raise, though he shouldn’t be surprised at Levi’s painfully obvious assessment. “You believe Eren is incapable.”

“No,” Levi grunts. “He’s as capable as any other mediocre soldier, only he’s been given an inhuman power. Ultimately, he’s a tool.”

“But that’s not your point,” Erwin guesses as Levi frowns at him in agitation. 

“No shit. Shut up and let me finish, old man.”

Erwin stills, suddenly aware of their dynamic as Levi’s emotions escalate just enough for him to emit a very distinctly alpha scent; they both go still, and Levi coughs, looking away.

“Sorry,” he mutters, taking a few steps back.

Erwin nods sharply, standing up with his hands behind his back to face Levi. “So, finish.”

“We’re different,” Levi says quietly, his fists clenching at his sides, “Ackermans. We all have something in common.”

“What’s that?” Erwin expects something along the lines of lethal killers or innately enhanced senses. He’s not expecting the actual answer.

“I don’t know how accurate this is,” Levi admits with a slight shrug, “but we… choose someone. Someone who…” He swallows hard, turning away, and Erwin realizes now what a terrible beating Levi’s pride is taking.

“Who is… what?” Erwin asks neutrally, keeping his voice even.

“Who we answer to.” Levi is scowling, humiliation evident in his face; he looks absolutely furious, but it’s not at Erwin.

“You don’t answer to anyone,” Erwin replies softly, frowning himself as he rounds his desk. “I’m sorry if I ever made you feel, after all this time, that you had to—”

“And it’s always an omega,” Levi finishes, his voice terse and cold. 

That gives Erwin pause, and he stops in his tracks before he can reach Levi with stiff shoulders and half fastened boots.

His mind reels for a moment, stacking up what Levi’s revealed, until he puts it together.

“I’m your shadow,” Levi spits, his words defensive and terse.

And before Erwin can even begin to understand, the door slams, and Levi’s gone.

Suddenly, Erwin can relate to Hanji’s shattered beaker Moblit had described before.

*

The day crawls, though Erwin only leaves his office once to retrieve hot water for his tea, absent-minded as he studies a field report in his hand.

He doesn’t even notice when he runs into his desk, sloshing the tea onto his blotter. He curses quietly, setting down the report, suddenly feeling as if he has something important to do.

He looks around the room, trying to remember; most things are in their regular places, except for Levi who’s normally here to provide comfortable silence in which to work.

It’s only then that he sees the glass of water sitting neatly at the side in one of the only clear places on his desk. Beside it, there’s a pill.

He sits down in his chair heavily and stares at it for a long time, almost dazed, before gulping it down. Something about it seems bitter, even though Levi obviously left it for him out of consideration.

He tells himself he wouldn’t have forgotten, but nonetheless, thanks Levi silently.

Levi manages to make himself scarce after that, though he’s not completely invisible; he starts to wonder if the strange bond Levi described hurts like a heat, if it’s maddening. Given his assessment of what it means to be an Ackerman, though, Erwin suspects there’s a touch of embarrassment there, to be swayed by a force out of his control.

But unlike a heat, Levi and Mikasa have some say in who they choose to answer to, not just a mindless need to serve. 

Erwin ponders Mikasa’s choice, knowing that she, Eren, and Armin Arlert were refugees together. Something about Eren, though, must have triggered her devotion. Even Erwin finds it uncanny sometimes, how it almost seems like her singular goal is to make sure Eren doesn’t hurt himself. He remembers her expression when Levi had beaten Eren to a bloody pulp tied to that post.

He wonders if Levi looks at him the same way.

Then again, Levi wanted to kill him the first time they met—there’s never been any doubt about that in Erwin’s mind. He tried a few times, in fact, and he probably would have in the forest if Erwin didn’t have words on his side.

But Levi chose to stay. He could have slipped away at any time, nothing to lose, yet he stayed; has stayed for years, always close by, a lethal shadow always willing to be dispatched.

There’s still some piece missing to the puzzle, though; some ache that Erwin continues to feel that doesn’t make sense based on biology or sensations out of their control.

It’s a few days after their confrontation that Erwin decides that it’s time to face the conflict head-on.

He decides to stop by Levi’s quarters, determined to lay this nameless issue to rest; though, as he makes his way through the barracks, he realizes that he can’t remember the last time he sought out Levi on his own.

Years ago, it would have been strange and invasive. Levi had stayed locked inside himself for a long time after the expedition that killed his friends, but somehow, without Erwin even noticing, he grew as accustomed to Levi’s presence as breathing.

He keeps his knock on the door soft, not wanting to startle Levi, since this is bound to be an uncomfortable conversation. It’s one they need to have, though.

The door swings open, and Levi looks surprised before he even sees Erwin; he obviously doesn’t get many visitors in his own rooms.

“Erwin,” he says, searching Erwin’s face for an explanation before Erwin can even open his mouth.

“May I come in?” he’s formal about it, polite.

Levi looks more curious than cautious, though, and he opens the door wider, motioning for Erwin to enter.

His quarters are absolutely spartan and unsurprisingly immaculate. Unlike Erwin’s rooms, which are strewn with books piled in random places and shirts placed on chairs that are often forgotten, Levi has barely anything on any surface. There’s a simple bureau in the corner—standard military issue—and a bedside table with a single book resting on its surface. Erwin recognizes it as one he’d lent to Levi from his library about different herbs that grow outside the Walls.

“What’s wrong?” Levi asks, crossing his arms and squinting at Erwin, looking utterly baffled.

He’s not wearing his gear, or cravat and jacket, and his hair is wet, as if he just bathed. He’s barefoot and most likely just returned to his quarters, ready to sleep. Levi is regimented when it comes to his own routine, unless Erwin’s irregular hours get in his way, which they often do. Just not as much lately.

“Nothing is wrong,” Erwin says diplomatically, folding his hands behind his back. 

There isn’t a single scent coming off Levi now, and Erwin knows his own scent is completely masked; for a moment, they just stare at each other, until Levi turns away to light another lamp on the other side of the room.

“So, why are you here?”

“I have a question,” he says carefully, taking a few steps back to give Levi as much room as possible, “about this… bond.”

Levi’s shoulders stiffen, but he gives no other outward response. His voice is even when he replies, “What about it?”

“Is it like having a mate?” Erwin questions, deciding to be blunt.

Levi looks at Erwin over his shoulder, eyebrow raised, and he shakes his head. “No.”

Erwin frowns, feeling more confused than when he’d first arrived, but he knows this issue is part of the reason Levi hasn’t been around as much, and that state of affairs is unacceptable for Erwin.

When Levi doesn’t offer up any alternative, simply turning to stare, expressionless, Erwin tries again.

“Like… a heat?”

Levi rolls his eyes, obviously not wanting to have this discussion, but as with so many other things, he humors Erwin.

“No.” He squints slightly, looking Erwin up and down as if he might find his Commander has succumbed to actual madness and lost his mind; he even sniffs the air a bit, but obviously, this provides no insight into Erwin’s intentions. “Why?”

“Why haven’t I seen you?” Erwin counters, unwilling to engage in a game of touch and go wordplay. He’s too tired, and too unhappy with the situation.

Levi hesitates, looking thoughtful rather than defensive now, and he settles on a simple shrug. “Maybe you’ve just been distracted.”

Erwin frowns at him now, crossing his own arms, recognizing the bullshit excuse for what it is.

“Why did you choose me?” he finally asks bluntly. “Why did you choose me, instead of killing me?”

The scowl that washes over Levi’s face is impressive, given his normal expression is already relatively dour, and he stares darkly. Erwin knows he doesn’t like talking much about the past, especially not the parts that involve that fateful day.

“I wanted to kill you.” He shifts, the stance defensive now, obviously fighting the urge to back away. “I hated you, and I hated you after joining the Corps.” He juts his chin out stubbornly, as if challenging Erwin to fire back. “I hated you for a long time.”

“And what happened?” Erwin meets the gaze, setting his own jaw firmly, unwilling to back down either. “What changed?”

They stare each other down, searching for any crack in one another’s stubbornness, but there is none. 

But since Erwin is the one who broached the topic, who sought Levi out to have this uncomfortable conversation—and given that Levi’s done nothing except mind his own business up until now—Erwin figures the least he can do is speak first.

“I’m asking,” he finally offers, averting his eyes. “It’s a question you don’t have to answer, but I’m _asking_.”

Levi seems to deflate, as his shoulders sink and his eyes drop to the floor, as if all the fight has simply drained from his body.

“It’s not like a heat or a mate,” he finally says, his voice quiet. “I think it was the second expedition outside the Walls.” He keeps his eyes down, his voice soft, as if he’s forcing himself to speak. “And I noticed the air finally. It’s fresher out there, not like the stink in this prison.”

Erwin shifts his stance, folding his hands behind his back as he listens intently, letting Levi take his time.

“Your words are pretty,” he continues after a moment. “You get terrified kids to join the Corps, even though there’s a good chance they’re going to die. You even convinced me not to kill you.”

Erwin inhales deeply; he knows all of this, and for anyone else, seeing his sins laid out in front of him is par for the course, something he’s not afraid of.

But Levi isn’t laying out his sins, because that’s not what Levi does.

“It took me a long time to stop listening to what you said,” Levi continues as he looks up, meeting Erwin’s eyes now, “and start listening to what you don’t say.” 

Erwin’s eyebrows raise, the statement unexpected. Of all people that Erwin speaks to, Levi is the one who seems to understand the most, able to dissect Erwin’s moods and intentions, pick apart any bullshit and call him on it.

“Why did you stop listening to me?” Erwin asks, unsure of what this assessment could possibly mean.

“To protect you,” Levi says, his voice very quiet now. “That’s what the bond mostly is—the urge to protect.” His eyes narrow slightly, pointedly giving Erwin a reproving look. “But it’s still a choice. It’s not a heat or some animalistic desperation.” 

Erwin feels like anything he was going to say has died in his throat, and he just stares openly at Levi now; it’s rare he’s taken off guard, but if Erwin had to guess who would be able to, it’d be Levi every time.

“What could I have possibly done to inspire that type of devotion?” Erwin asks, his voice quiet and solemn. 

Levi shifts, standing up straighter and he says without a hint of shame, “You gave me the air.” He finally steps forward instead of backing away, getting into Erwin’s personal space. “You gave me freedom.”

They just stand there, looking at each other, and the tension is so strong Erwin can almost taste it.

They grab each other at the same time—Levi dragging Erwin down by his bolo tie as Erwin grips Levi’s shoulders—a tangle of touches and violent kisses pressed against any skin they can find, until Erwin’s shirt is open and Levi’s mouthing hungrily at his chest.

“Fuck,” Erwin groans, fisting his hand in Levi’s hair as he feels teeth close around his nipple and a hand slide between his legs that pushes against his cock with tantalizing pressure.

Erwin is desperate to touch, to get Levi naked and under him, to fuck him until he cries with pleasure; in some way, it’s almost like a heat haze, but it’s not the same. 

“Fuck,” Levi echoes, practically panting as he rests his forehead against Erwin’s shoulder, trying to catch his breath. 

And Erwin realizes how stupidly simple this is—that outside the complexities of bonds and biology, there’s just Levi, sitting in his office drinking tea, cracking caustic jokes and allowing Erwin to be tired without hiding it.

He pushes Levi back toward the bed, walking them there together, feeling a surge of lust run through him as Levi arches against him, all grace and power and fluidity. Then Erwin does smell him, smells the way the alpha scent hums there just underneath the surface; and Erwin wonders if by some miracle, Levi can pick up his scent even underneath all the layers that hide it, the layers that hide him.

They fall onto the bed together, hands everywhere, roving over each other’s bodies, kissing and touching wherever they can like dizzy dragonflies skimming across water in the swelter of summer.

Erwin undresses Levi quickly, pulls his pants and underwear off, unbuttons his shirt and pushes it off his shoulders, but then he slows down to really _look_.

During the heat, he had barely touched Levi at all; but he’d wanted to. And he realizes, as Levi stares up at him with the first soft look Erwin’s ever seen him allow, that he’s wanted to for a long time.

The first cry out of Levi’s mouth when Erwin bends to kiss his chest and give his cock a few strokes is intoxicating, and makes Erwin’s cock throb in the pants he’s still wearing; he wants Levi to scream, to pant, to say his name.

“Erwin,” Levi moans, back arching as Erwin starts to stroke him evenly, hips canting. His face is tense, but instead of his usual scowl, his eyebrows are raised like he might cry, mouth fallen open as he tries to breathe, and slurs out Erwin’s name again.

“I’m here,” Erwin whispers, lying down next to him and pulling his hand away, kissing at Levi’s shoulder.

“Get your fucking clothes off,” Levi whispers, rolling onto his side to wrap his leg around Erwin’s hip, rutting lazily against him.

Erwin intends to just that, but he’s distracted by the way Levi moves his hips, his breath against Erwin’s chest with his shirt still half unbuttoned.

Levi draws away after a moment, obviously exerting substantial will power to do so to allow Erwin to undress, and Erwin makes quick work of his clothes, shrugs out of the shirt and kicks off his pants and underwear until they’re both naked.

He doesn’t think as he grabs Levi, maneuvers him onto his back and gets on top; Levi gives as good as he gets, splaying his hands across Erwin’s shoulder blades and pulling him closer, one of his hands sliding up into Erwin’s hair as they rut against each other, cocks slick with precome sliding together. 

The motions become slower, and Erwin pants heavily into Levi’s neck as he moves his hips, reaching down to stroke them together, his hand moving quickly. Levi’s breath starts to come in short gasps, until finally, he gives a sharp cry and comes, his hand tightening almost painfully in Erwin’s hair.

“Fuck,” Erwin breathes as Levi rides out his orgasm and then relaxes, pressing their foreheads together.

And then he’s being pushed onto his back, Levi’s mouth on his chest, his stomach, moving steadily downward. 

“Want you,” Levi murmurs in between kisses, moving to kneel between Erwin’s legs and squeeze gently at his balls. A violent shiver runs through Erwin as he spreads his legs wider, not knowing at this point whether he’s reacting to an alpha’s scent, Levi’s touch, or the urge to fuck Levi into oblivion. Maybe it’s all three.

He opens his eyes, and for a moment, just watches Levi. His dark hair is hanging in his face as he’s slowed down, mouthing at Erwin’s hips and stomach with great concentration, eyes closed as he tastes and inhales deeply. His shoulders aren’t broad, but they’re strong, and Erwin reaches down to tilt his chin up.

“Levi,” he says softly, pulling Levi up so that they’re face to face, and then slides his fingers down to the small of Levi’s back.

“Yeah,” Levi pants, pressing his face against Erwin’s chest as he feels the motion, “fuck, yes.” He points weakly at the bedside table. "Top drawer."

Erwin fumbles with his free hand for the drawer while keeping Levi on top of him, fingers stroking at his back, fingers finally landing on the vial of lubricant he’s looking for.

Levi grabs it impatiently and opens it, slicking up Erwin’s fingers; Erwin doesn’t hesitate as he slides his hand down to Levi’s ass again, slowly teasing him which earns a grumble that makes Erwin smile slightly, and then presses against his hole.

“Good?” he asks as he starts to slip his finger inside. Levi’s tight, and he keens as he spreads his legs more, pushing back against Erwin’s finger.

“Yeah,” he pants, sounding completely out of control, “keep doing that. Erwin, fuck…”

Erwin moves his finger slowly at first, letting Levi get used to it, but then starts to fuck him, adds another, until Levi is riding two fingers wildly. His grip is painfully tight, fingers wound around Erwin’s bicep, but Erwin doesn’t mind, liking the show of strength as a counterpoint to Levi falling apart.

He stops moving slowly, though, pressing their mouths together in a languorous kiss, and Erwin pulls his fingers out; he thinks he knows what Levi wants, but he waits.

“I want you to fuck me,” Levi says softly, reaching for the lube again as he sits up slowly.

Erwin just watches him intently as Levi draws up to his knees, trying to catch his breath as he pours some lubricant into his palm, and then slides his hand along Erwin’s length, slicking him up.

Erwin groans and tilts his head back, eyes fluttering shut as Levi strokes him; it’s slow this time, not frenzied with the desperation and pain of a heat. He gradually speeds up his strokes, though, and Erwin starts to fuck the tight circle of his fingers, forcing his eyes open to look down at Levi.

He finds that Levi is watching him just as closely, studying his face, and their eyes lock.

They keep staring at each other even as Levi stops and positions himself over Erwin’s cock, slowly sinks down onto it and lets Erwin slip inside, easy and smooth until his thighs are flush with Erwin’s.

Erwin feels heat and possessiveness shimmer through him, and he sits up, using his full strength to reposition them so that Levi’s sitting in his lap as he starts to fuck up into him. Levi’s legs are wrapped tightly around his hips as they move together, Erwin seated deep inside as Levi wraps his arms around Erwin’s neck.

“Erwin,” he hiccups wetly as Erwin thrusts up into him, his legs shaking.

“Good?” Erwin pants, working his body hard to fuck Levi the way he wants it, craving that tight heat like nothing he’s ever known, wanting Levi’s voice vibrating against his shoulder as he moans, breath hitching when Erwin hits at just the right angle.

“You feel so good,” he breathes harshly, “Levi…”

Levi lets his head dip forward, mouthing against Erwin’s neck; and then Erwin goes rigid as he feels hair tickle his cheek, Levi's lips so close to his scent gland.

And Erwin simply tilts his head to the side, and waits.

When Levi marks him, bites him there and then rubs their scents together, Erwin comes; his cock pulses twice, emptying him in ways he never thought possible, clinging to Levi.

Levi takes a deep, deep breath, then exhales slowly, pressing his nose against Erwin’s scent gland a few times. It says: _mine, mine._

And Erwin murmurs when he finds his voice again, “I’m yours.” 

They both exhale together, and finally, Levi pulls off Erwin’s cock and collapses on the bed next to him. Erwin follows and immediately pulls Levi close, breathing shallowly as Levi licks at his neck, touches Erwin’s side and smooths a hand over his skin.

“What is this?” Erwin finally asks, closing his eyes and letting Levi touch him.

There’s a short silence, but when Levi finally speaks, he’s quiet. “Remembering to breathe.”

Erwin sighs, accepting the answer; somehow, it fits. 

And so, he lies there with his mate, his shadow, breathing in sync, and he knows the smell of fresh air for the first time.

**Author's Note:**

> You may have noticed that I messed with canon details, like Levi actually knowing what the Ackerbond is. This may or may not be possible/true, but for the purposes of this story, he does know what it is.
> 
> Thank you for reading, and I hope you enjoyed! <3
> 
> I have a [tumblr](http://flecksofpoppy.tumblr.com). :D


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